Pros:

-Looks good.
-Works real well.
-Great addition for TF2 Survivors.
-Perfect for TF2 fans.

Cons:

-First person arms look a bit jagged and squashed.
-Friendly fire incidents can occur if used with the Painis Cupcake Witch skin. (No points deducted)
-No facial expressions (No points deducted)

Conclusion:

It's a good mod. A must for TF2 fans far and wide. Having all the mercs would be very cool. Just don't use it with the Painis Cupcake Witch skin, though.